In the LTE system, because there is only packet switching (PS) domain, voice services are carried by the Internet Protocol (IP), which is strict in requirement for time delay. The time for the UE to transit from idle state to active state cannot be more than 100 milliseconds, thereby making a strict requirement for design of the whole LTE system. In the LTE system, the process that the base station, i.e., Evolution Node B (eNB) obtains UE radio capability information is one of the important processes in the process that the UE transits from idle state to active state, so the time delay of the process of obtaining the radio capability information of UE is also one of the important influence factors of the time delay of the whole afore-mentioned process.
FIG. 1 illustrates a diagram of interface relationship among UE, eNB and Mobility Management Entity (MME) in the LTE system; as shown in FIG. 1, the interface between the UE and the eNB is UU interface which is a radio interface; the interface between the eNB and the MME is S1 interface which is a wire interface; the MME is an entity of the Core Network (CN).
The UE radio capability information comprises system supported by the UE (which means radio technology), frequency range, protocol edition, radio frequency capability, measurement capability, physics layer capability and so on; and different systems have different capabilities. At present, the radio capabilities of UE comprise EUTRA capability (see the detailed definition in TS36.331), UTRAN capability (see the detailed definition in TS25.331), GERAN capability (see the detailed definition in TS24.008 and TS44.018).
In the LTE system, there are two methods for eNB to obtain the UE radio capability information.
First method: when the UE radio capability information has been stored in the MME, the MME includes the UE radio capability information in the initial context setup request message sent to the eNB, and the eNB stores the UE radio capability information after receiving the initial context setup request message.
Second method: when no UE radio capability information is stored in the MME, the initial context setup request message sent to the eNB contains no UE radio capability information, which triggers the eNB to send the UE a query message of the UE radio capability information, called query message for short. The querying method is specifically that: the eNB sends a query message to the UE, the UE sends the UE radio capability information of corresponding access technology to the eNB according to the access technology type contained in the query message, and then the eNB stores the UE radio capability information and sends the UE radio capability information to the MME.
In the second method above, the triggering part which triggers the eNB to query the UE about radio capability is the MME; since both the MME and the eNB do not know which radio access technology the UE supports, when querying the radio capability with the UE, the eNB does not know which radio access technology type should be written, which causes the eNB to be in blindness state when querying the radio capability with the UE. The method adopted in the prior art is including all radio access technology types supported by protocol in the query message. However, with the development of radio technologies, there will be more and more access technology types, so more and more access technology types are needed to be included in the query message. Since the UE radio capability information of each access technology is relatively large, usually taking up dozens of bytes, the more the queried access technology types are, the more the UE capability information sent by the UE to the eNB is, which increases the overhead of the air interface, and thereby directly influencing the connection delay of the UE.